Relationship of fetal macrosomia to a 75g glucose challenge test in nondiabetic pregnant women.

Abstract

We determined in nondiabetic women, the relationship of plasma glucose values obtained 2 hours after a 75 g oral glucose challenge test (GCT) at 16-20 weeks' gestation, with the incidence of macrosomia in term deliveries (37-41 weeks' gestation). From 1988-1990, in a systematic screening programme data collected prospectively from 1,331 women were analysed retrospectively. Women with gestational diabetes or impaired glucose tolerance (n = 53) were excluded. The rest (n = 1,278) had no evidence of glucose intolerance including 1,215 women with normal plasma glucose by GCT (< 7.8 mmol/L 2 hours after 75 g oral glucose load) and 63 women with abnormal GCT but not abnormal value at a glucose tolerance test. The GCT values were divided into 5 groups: Group A (< 4.5 mmol/L), B (4.5-5.5 mmol/L), C (5.6-6.6 mmol/L), D (6.7-7.7 mmol/L) and E (> 7.8 mmol/L). The variables studied were age, parity, gestational age at delivery and incidence of macrosomia. Using > 4 kg birth-weight as the definition of macrosomia, the incidence increased from 1.2% to 9.5% with increasing plasma glucose values in the GCT from Group A (> 4.5 mmol/L) to E (> 7.8 mmol/L). Similar trends of increasing incidences from 7.2% to 15.8% and 2.9% to 9.5% were noted when 90th and 95th birth-weight percentiles, respectively were used as definitions of macrosomia. The test of linear trend in this association was significant (p < 0.01). These results were not influenced by parity or gestational age at delivery.(ABSTRACT TRUNCATED AT 250 WORDS)